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calc/help/atan2
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NAME
atan2 - angle to point
SYNOPSIS
atan2(y, x, [,eps])
TYPES
y real
x real
eps nonzero real, defaults to epsilon()
return real
DESCRIPTION
If x and y are not both zero, atan2(y, x, eps) returns, as a multiple of
eps with error less than abs(eps), the angle t such that
-pi < t <= pi and x = r * cos(t), y = r * sin(t), where
r > 0. Usually the error does not exceed abs(eps)/2.
Note that by convention, y is the first argument; if x > 0,
atan2(y, x) = atan(y/x).
To conform to the 4.3BSD ANSI/IEEE 754-1985 math lib, atan2(0,0)
returns 0.
EXAMPLE
; print atan2(0,0), atan2(1,sqrt(3)), atan2(17,53,1e-100)
0 ~0.52359877559829887307 ~0.31038740713235146535
LIMITS
eps != 0
LINK LIBRARY
NUMBER *qatan2(NUMBER *y, *x, *acc)
SEE ALSO
acos, asin, atan, cos, epsilon, sin, tan
## Copyright (C) 1999,2021,2023 Landon Curt Noll
##
## Calc is open software; you can redistribute it and/or modify it under
## the terms of the version 2.1 of the GNU Lesser General Public License
## as published by the Free Software Foundation.
##
## Calc is distributed in the hope that it will be useful, but WITHOUT
## ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
## or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General
## Public License for more details.
##
## A copy of version 2.1 of the GNU Lesser General Public License is
## distributed with calc under the filename COPYING-LGPL. You should have
## received a copy with calc; if not, write to Free Software Foundation, Inc.
## 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
##
## Under source code control: 1994/03/19 01:40:26
## File existed as early as: 1994
##
## chongo <was here> /\oo/\ http://www.isthe.com/chongo/
## Share and enjoy! :-) http://www.isthe.com/chongo/tech/comp/calc/